Ligating clip applying instrument

ABSTRACT

A polymeric, surgical clip having first and second curved leg members joined at their proximal end by a reduced thickness hinge portion and movable from an open position to a closed position for clamping a vessel between curved opposing inner surfaces which are substantially parallel when the clip is closed. The first leg member has a concave inner surface and a hook portion at its distal end curved toward the second leg member. The clip includes a sharp distal tip on the end of the hook portion and a sharp pointed penetrating member on the outer surface of the distal end of the hook portion. The distal end of the second leg has a longitudinal groove through which the sharp pointed penetrating member and then the sharp distal tip passes when the legs are closed. The second leg member further comprises a pair of sharp penetrating member attached to each side of the distal end on either side of the groove. These cooperate with the penetrating member of the first leg and sharp distal tip to cut tissue attached to the vessel to be clamped. A ligating clip applying instrument for applying the clip has a pair of handles pivoted about a hinge point and extends beyond the hinge point to form a pair of clip closing jaws equipped with means for engaging bosses located on the sides of the first and second leg members.

This is a divisional application of application Ser. No. 07/422,464filed Oct. 17, 1989, now U.S. Pat. No. 5,062,846, which is acontinuation-in-part of application Ser. No. 329,453, filed Mar. 28,1989, now abandoned, which was a divisional of application Ser. No.206,143, filed Jun. 13, 1988, now U.S. Pat. No. 4,834,096, issued May30, 1989, which was a continuation-in-part of application Ser. No.112,599, filed Oct. 26, 1987, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to surgical clips and clip appliers andmore particularly to penetrating polymeric hemostatic clips andinstruments for applying them.

Surgical clips like hemostatic clips and aneurysm clips are often usedin surgery to ligate vessels to stop the flow of blood. Surgical clipsare also used to interrupt or occlude the oviduct or vas deferens insterilization procedures. The clips are left in place permanently andwithin a period of time the ligated end of the vessel will close, thatis, hemostasis or occlusion will occur.

Metal clips having generally U or V shapes have been used for years. Themost common metals are alloys of tantalum, titanium or stainless steel,all of which are deformed into a closed position about the vessel andbecause of the nature of the metal stay deformed and resist any force bythe vessel to expand or open up.

Metal clips cause a certain amount of interference with high technologydiagnostic modalities, including Computer Tomography (CATSCAN) andMagnetic Resonance Imaging (MRI). In particular, the new and emergingMRI techniques place stringent demands on the non-interferenceproperties of clips. For example, existing fast imaging techniques forMRI give rise to at least one order of magnitude in increasedsensitivity to magnetic field inhomogenieties brought about by metallicclips. Field uniformities of one in 10⁵ are required but metal clips,particularly stainless steel clips, can reduce the homogeniety in thelocality of the clip to the order of 10⁴ or less.

To aggravate the situation even more recent developments in in vivoMagnetic Resonance Spectroscopy (MRS) create even greater demands onminimizing magnetic field interferences (field uniformitiesapproximately one in 10⁷ required). Existing metal clips preclude theuse of MRS data taken in the proximity of the metal clips. This regionis as large as six clip diameters for titanium and tantalum and morethan fifty clip diameters for stainless steel.

To overcome the above problems, in recent years plastic clips have beenintroduced. These clips generally should be as small as possible, e.g.,as small as their metal counterparts. Plastic clips require a latchingmeans to keep the clip closed once they are clamped about the vesselsince, unlike metal clips, they have insufficient resistance to theforces tending to open the vessels. The requirement to latch presents anadditional problem since the polymeric clip must surround the vessel todo so. Therefore, the vessel to be ligated must not be attached to anysurrounding tissue. Without more, such clips would require that thesurgeon dissect the vessels from the surrounding connective tissue andthis would be very time consuming. With metal clips this is notnecessary since metal clips need not surround the vessel to occlude it.It is desirable, therefore, to provide a polymeric clip capable ofoccluding a vessel attached to connective tissue.

Most of the new plastic clips now in the market are made of abiodegradable and absorbable polymeric material. Generally, theabsorbable clips, owing to their comparatively high water sorption donot reflect the mechanical strength levels which are available frommodern engineering plastics and therefore represent a size increasecompromise in order to provide comparative strength. The use of highperformance polymer materials permits increased design options forfunctional improvements.

It is, therefore, desirable to produce a small, but secure,biocompatible and strong polymeric surgical clip which may be used toclose vessels connected to surrounding tissue.

SUMMARY OF THE INVENTION

The surgical clip of the present invention is made of polymeric materialand accordingly minimizes interference with high technology diagnosticmodalities such as CATSCAN, MRI and MRS. At the same time, the clip isnearly as small as comparable metal clips, while maintaining sufficientstrength and possessing high security in the clip's latching mechanismin the closed position clamping the vessel. The clip is configured toprovide a secure means of handling and application to avoid prematurerelease from the applier, and includes means for penetrating throughsurrounding tissue connected to the vessel.

A surgical clip is provided which comprises first and second curved legmembers joined at their proximal ends by a hinge means and disposed tobe latched together in the closed position at their distal ends. The legmembers each include complementary curved, opposing inner surfaces, theinner surface of the first leg being concave in shape. The first legmember further includes a hook portion joined at its distal end andcurved toward said second leg member. The hook portion includes acontinuously curved outer surface extending from the outer surface ofthe distal end of the first leg and a distal tip portion forming a sharppointed distal tip extending rearwardly toward the proximal end of thefirst leg. The hook portion may also include a sharp pointed memberattached to the outer surface of the distal tip portion.

The hook portion is disposed to engage the outer surface of the distalend of the second leg member when the clip is in the closed position.The distal end of the second leg member includes a groove through whichthe the sharp pointed distal tip presses when the first and second legmembers are moved from the open position to a closed position. Where theclip includes a sharp pointed member the sharp pointed member passesthrough the groove ahead of the sharp pointed distal tip. The sharppointed member engages, stretches and penetrates connective tissueconnected to the vessel to be clamped. In the stretched position, theconnective tissue is more easily penetrated and cut by the sharp distaltip as the clip is closed.

To assist in cutting the connective tissue to allow the clip leg membersto latch, sharp penetrating members are attached on either side of thedistal end of the second leg member on either side of the groove. Eachmember has a sharp distal tip which extends beyond the inner surface ofthe second leg member. Preferably, the radius of curvature of the distaltips of the distal tip portion of the first leg and the sharp pointedmembers of the second leg are less then 0.002 inches in their principalplanes.

The outer surface of the second leg member opposite the inner convexsurface is concave in shape. This configuration provides a more securelatching mechanism, since any forces by the clamped vessel tending toopen the clip will force the second leg to lengthen and the first legmember to shorten moving the distal end of the second leg member intofurther engagement with the hook portion. Because the thickness of thesecond leg member is smaller than it would have been without the concaveouter surface, the second leg member will deflect upon clamping or inresponse to the forces exerted on it by the clamped vessel and becausethe thickness of each leg between its inner and opposite outer surfacesbetween the hinge and distal end is substantially equal to the thicknessof the other leg, the total deflection necessary to accommodate closingand clamping of the vessel is distributed between the two legs helpingto avoid breakage or failure of either leg. In the preferred embodiment,the radius of curvature of the inner concave surface of the first legmember is the same as the radius of curvature of the inner convexsurface of the second leg member. This provides a constant compressiveforce across the entire width of the vessel being clamped.

The inner and outer surfaces of the hook portion are substantiallycontinuously curved to prevent excessive stress concentration occurringat corners or small radius points in the hook portion.

The clip further comprises means for allowing the clip to be engaged bya suitable forceps type applier comprising at least a pair of bosseslocated on the sides of the first leg member intermediate the hingemeans and the hook portion and a pair of bosses also located on thesides of the second leg member at the distal end. The sharp pointedmembers extend from these bosses. The bosses are so disposed as toextend beyond the end of the second leg member to provide two paralleland separately spaced surfaces which prevent lateral movement of the legmembers relative to one another when the clip is closed. The bosses areused by the applier in holding and applying the clip.

The clip of the present invention may also include a plurality ofprotrusions on the inner surfaces of the leg members to aid in retentionof the clamped vessel. The protrusions may be ratchet type, wedgeshaped, to provide one way vascular movement into, but not out of, theclip.

A ligating clip applying instrument for applying two legged ligatingclips having means for engaging the bosses located on the sides of thelegs is also provided. The jaws of the instrument include a channel toreceive the clip and a concave cut out near the end of each jaw. Eachwall may also include an arcuate wall portion adjacent to and on theoutside of the cut out.

The instrument further comprises a protrusion in the floor of each ofsaid channels which is directed toward the opposite jaw, the protrusionbeing located proximally of the concave cut outs. Each protrusionengages a leg of the clip to assist in forcing the legs toward oneanother as the jaws are closed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged perspective view of the surgical clip of thepresent invention.

FIG. 2 is a side elevational view of the clip of FIG. 1.

FIG. 3 is a front elevational view of the clip of FIG. 2 looking intothe open end of the clip.

FIG. 4 is a cross-sectional view of the clip of FIG. 2 taken along thelines and arrows 4--4 in FIG. 2.

FIG. 5 is a top view of the distal end of a leg portion of FIG. 2 takenalong the lines and arrows 5--5 in FIG. 2.

FIG. 6 is an end view of the distal end of another leg portion of FIG. 2taken along the lines and arrows 6--6 in FIG. 2.

FIG. 7 shows the clip of FIG. 1 applied to a body vessel.

FIG. 8 illustrates an enlarged planar elevational view of a forceps typeapplier useful with the clip of the present invention.

FIG. 9 is a greatly enlarged perspective view of a break away of a firstjaw of the applier of FIG. 8.

FIG. 9A is a bottom planar view of the first jaw of FIG. 9.

FIG. 10 is a greatly enlarged perspective view of a break away of asecond jaw of the applier of FIG. 8.

FIG. 10A is a bottom planar view of the second jaw of FIG. 10.

FIG. 11A and 11B are greatly enlarged perspective views of an alternateembodiment of the jaw portion of the applier of FIG. 8.

FIGS. 12A to 12E illustrate the use of the applier of FIGS. 11A and 11Bin applying the clip of the present invention.

FIGS. 13A through 13E show in enlarged detail the hook portion of oneleg member and the distal end of the other leg member in variousprogressive stages of closure penetrating connective tissue attached tothe vessel being clamped.

FIG. 14 is a side elevational view of an alternate embodiment of theclip of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to FIGS. 1-6, a preferred embodiment surgical clipdesignated generally 10 is shown. It comprises a first curved leg member12 and a second curved leg member 14 joined at their proximal ends by ahinge portion 16.. First leg member 12 has a concave inner surface 20and a curved hook portion 22 joined at its distal end. The inner surface24 of second curved leg member 14 is convex and is adapted to besubstantially parallel with concave inner surface 20 when the clip isclosed, i.e.; the radius of curvature of the concave inner surface 20 issubstantially the same as the radius of curvature of the inner convexsurface 24. The hook portion 22 is curved toward the distal end ofsecond leg member 14.

The hook portion 22 comprises a continuously curved outer surface 28which continues from the convex outer surface 30 of the first leg memberwith decreasing radius of curvature. The inner surface of the firstcurved section is continuously curved and continues from the innerconcave surface 20 of the first leg member 12 in a decreasing radius ofcurvature to a constant terminal radius of curvature. The first legmember 12 further comprises generally flat parallel side surfaces 25 and27 which extend between the inner and outer surfaces of the first legmember and the the hook portion 22. In the preferred embodiment thethickness of the first leg member between its inner and outer surfaces20 and 30, respectively, and most of the hook portion between its innerand outer surface 26 and 28, respectively, remains generally constantthroughout its length.

The hook portion 22 terminates in a distal tip portion 29 which extendsrearwardly and itself terminates in a sharp pointed distal tip 31 whichpoints generally toward the proximal end of the clip 10. As best seen inFIG. 4, the sharp tip 31 is formed by inwardly tapered surfaces oddnumbers 33 through 39. Surfaces 33 and 35 converge and narrow to the tip31 from side surfaces 25 and 27, respectively; surface 37 converges andnarrows from a flat surface 41 which extends to the terminal radius ofcurvature portion of inner surface 26; and surface 39 converges from thecurved surface 28 of the hook portion. To enhance the penetrationeffect, the radius of curvature of the tip in the center plane of theclip and in a plane orthogonal thereto should be less then 0.002 inches.This compares favorably with the sharpness of a skin staple tip.

The distal tip portion 29 of the first leg member further includes asharp pointed member 43 attached to the outer surface of the portion 29.The member 43 is formed from a sloped surface 45 which extends away fromthe curved outer surface of the distal tip portion and the sharp tip 31,somewhat in a direction away from the hinge portion of the clip. Itcomprises sloped sides 47 and 49 (see FIGS. 4 and 5) and an edge 51which returns to the curved outer surface of the hook portion 22. Theexterior tip 53 of the sharp pointed member 43 has a radius of curvatureof approximately 0.002 inches.

The second leg member 14 has a banana like profile along its lengthbetween its inner convex surface 24 and outer concave surface 38. Thethickness of the distal end has a rapid reduction in thickness becauseof the change in radius of curvature of its inner surface 24 at 42 toform a curved inner beveled surface 44 terminating in a curved tip 46and the relatively flat beveled surface 48 joining the outer concavesurface 38 to the tip 46. The distal end of the second leg includes agroove 61 in the center plane of the clip which passes through the tip46. As best seen in FIGS. 3 and 6 the groove 61 is formed by inwardlydirected tapered side walls 63 and 65 cut into the distal end of thesecond leg member. The bottom of the groove is represented by line 67.

The thickness of the second leg member 14 between its inner and outersurfaces 24 and 38, respectively, between the hinge portion 16 and itsdistal end may vary by ten to twenty percent with the leg being thickestat its center region. Generally the thickness of the second leg 14 issubstantially the same as the thickness of the first leg 12 except forthis variation in the center where the second leg may be slightlythicker. The thickness of the first leg 12 could be increased, however,in the center region to match the thickness of the first leg by varyingthe outer convex surface 30 of the first leg 12 but the radius ofcurvature of the concave inner surface 20 remains equal to the radius ofcurvature of the convex inner surface 24 of the second leg member 14.The thickness of the second leg member 14 being slightly thicker in thecenter causes the first leg member to deflect a little more than thesecond leg member when the clip is being clamped about a vessel, but thesecond leg member is disposed because of its outer concave surface todeflect substantially during closure so that total defection of the legsnecessary to clamp a vessel and latch the clip is being shared aboutequally by the legs.

Hinge portion 16 comprises an inner continuously curved concave surface50 which joins the inner concave and convex surfaces 20 and 24,respectively, and an outer continuously curved surface 52 which joinsouter convex and concave surfaces 30 and 38, respectively, and which isspaced apart from inner hinge concave surface 50. The hinge portion 16further includes a curved slot 55 which is located between curved hingesurfaces 50 and 52, being positioned closer to concave hinge surface 50than to convex hinge surface 52. The slot extends completely through thehinge portion 16 from side to side and its opposite ends 71 and 73extend into the proximal ends of the leg members 12 and 14,respectively. The slot 53 provides added flexibility to the hinge 16 butthe inner concave surface 50 prevents any portion of the clamped vesselfrom being trapped within the slot 53.

Leg member 12 includes a pair of cylindrical bosses 68 and 70 coupled onopposite sides of leg member 12 intermediate the hook portion 22 and thehinge portion 16, but closer to the hook portion 22 in the preferredembodiment. The bosses extend laterally away from the leg member beyondthe outer surface 30 of the leg member 12. The bosses are coupled to oneanother across the width of leg member where they extend beyond theouter surface 30 for a cylindrical portion 68'.

Leg member 14 includes a pair of cylindrical bosses 72 and 74 located atthe tip 46 on opposite sides of the leg member 14 and extendinglaterally away therefrom. In the preferred embodiment, the coaxialcenter line of the bosses 72 and 74 passes through the tip portion ofthe leg member 14. The bosses 72 and 74 extend beyond the tip leavingspaced apart opposing surfaces 76 and 78, respectively.

The second leg member further includes a pair of sharp penetratingmembers 77 and 79 extending from the bosses 72 and 74, respectively,past the inner surface 24 of the leg 14. The sharp penetrating membersare located on either side of the groove 61 and terminate in sharp point81 and 83, respectively. The sharp points 81 and 83 are in a plane withthe plane of the interior boss surfaces 76 and 78, respectively (seeFIG. 3). The tips have a radius of curvature in that plane ofapproximately 0.002 inches.

FIG. 8 shows a forceps type clip applier 80 which includes two handles82 and 84 coupled together and crossing at a hinge 86. The handles arebiased into an open position by the spring 88. The handles 82 and 84extend beyond the hinge 86 to form jaws 90 and 92, respectively.

FIG. 9 is an enlarged break away of a portion of the jaw 90 while FIG.9A is a planar view of the jaw 90 of FIG. 9 both showing the details ofits construction. The jaw 90 includes a channel 96 which extends from aposition 97 rearward of the tip of the jaw towards the tip. Thethickness of the outside walls 98 of the channel widen as they approachthe end of the jaw to form arcuate outside walls 100 of the end of thejaw and inward adjacent walls 102 with rearwardly directed slopedsurfaces 103 and concave cut outs 104. The inner surfaces of the walls102 are contiguous with and in the same plane as the inner surfaces ofthe walls 98 which form the channel 96. Where the walls 98 widen to formthe outside arcuate walls 100 and adjacent walls 102, the cut outs 104extend beyond the top surfaces of the walls 98 toward the opposite jawto form rounded shoulders 105. The adjacent arcuate walls 100 also areraised above the top surfaces of walls 98 by the same amount. The floor99 of channel 96 is spaced apart and parallel with the top surfaces ofwalls 98 of the jaw along a portion extending from the rearward terminus97 of the channel until the floor extends towards the opposite jaw alongramp 101 to form a protrusion 108 located just as the cut outs 104extend above the top surfaces of walls 98. The protrusion 108 dropsstraight off to a flat portion 128 of the jaw which flat portion extendsto the tip. The jaw has a flat outer bottom surface 106.

FIG. 10 is an enlarged break away of a portion of jaw 92 while FIG. 10Ais a planar view of the jaw 92 of FIG. 10 both showing the details ofits construction, which are identical to the construction of jaw 90. Thejaw includes a channel 110 which extends from a position 112 rearward ofthe tip of the jaw toward the tip. The outside walls 114 of the channelwiden as they approach the end of the jaw to form arcuate outside walls116 of the end of the jaw and inward adjacent walls 118 with rearwardlydirected sloped surfaces 119 and concave cut outs 120. The innersurfaces of the walls 118 are contiguous with and in the same plane asthe inner surfaces of the walls 114 which form the channel 110. Wherethe walls 114 widen to form walls 116 and 118, the cut outs 120 extendtowards the opposite jaw beyond the top surfaces of walls 114 to formrounded shoulders 121. The arcuate walls 116 extend beyond the topsurface by the same amount. The floor 111 of channel 110 is spaced apartand parallel with the top surface of walls 114 of the jaw along aportion extending from the rearward terminus 112 of the channel untilthe floor extends towards the opposite jaw along ramp 125 to form aprotrusion 124 located just as the cut outs 121 extend above the topsurfaces of walls 114. The protrusion 124 drops straight off to thebottom of the jaw which extends to the tip. The jaw has a flat outerbottom surface 122.

FIGS. 11A and 11B show an alternate embodiment of the jaw of the clipapplier of FIGS. 8 through 10A. Like parts are labelled with a prime'.The clip applier includes two handles like handles 82 and 84 coupledtogether and crossing at a hinge 86 (not shown in FIGS. 11A and 11B).The handles are biased into an open position by a spring, like spring 88in FIG. 8. The handles extend beyond the hinge to form identicalopposing jaws. Jaw 92' is shown by way of example. The lower jaw isidentical. Referring to FIG. 11A, the jaw 92' includes a channel 110which extends from a position rearward of the tip of the jaw toward thetip. The channel is formed by outside walls 114' which have distalportions with rearwardly directed sloped surfaces 119' and concave cutouts 120'. Just behind the cut outs 120', the walls 114' extend towardthe opposite jaw to form shoulders 121' which protrude above the topsurfaces of the walls 114' which are proximal of the shoulder. The floor(not shown) of channel 110' is spaced apart and parallel with the topsurfaces of the proximal portions of walls 114' along a portionextending from the rearward terminus of the channel until the floorextends towards the opposite jaw along ramp 125' to form a protrusion124' located just as the shoulder's 121' extend above the top surfacesof walls 114'. The protrusion 124' drops straight off to the bottom ofthe jaw. The cut outs 120' are formed in wall portions of the distalportion of the jaws which are parallel and spaced apart from one anotherand are unconnected along their bottom edges 126'.

FIGS. 12A through 12E show how the applier of FIGS. 11A and 11B is usedin applying the clip 10. The applier of FIGS. 8-10A would work as well.The clip 10 is in the open position with the general axes of the legmembers 12 and 14 forming an acute angle at the hinge, but the clipcould be open as much as 90° or more. The jaws of the applier 92' arebiased open by an amount equal to the opening of the clip. As theapplier is moved in the direction of arrow 1200 in FIG. 12A, the bosses72, 74 and 68, 70 (only bosses 68 and 72 are shown) are forced to rideup the rearwardly directed inclined surfaces 119' of the distal portionsof the walls forcing the clip to close slightly until the bosses seat incut outs 120' as in FIG. 12B.

The cut outs of each jaw are spaced apart from one another by thechannel of each jaw which is at least as wide as the width of the clipand the cut outs are disposed to receive the bosses. The concave cutouts keep the clips aligned and locked within the jaws, during theclosing. The concave cut outs 120' press against the bosses to beginclosure of the clip.

After the boss pairs 72, 74 and 68, 70 seat themselves in the concavecut outs, the raised shoulders 124' of jaws 92', respectively, pressagainst the outside surfaces of leg members 12 and 14 to continueclosure of the clip 10 (see FIGS. 12B-12E). Eventually the outsidesurface 32 of the hook portion 22 engages the inner surface 24 of legmember 14 near the curved bevel surface 44. See FIG. 12C. As the legmembers continue to be pressed together, the rounded outside surface ofthe hook portion 22 slides along the curved bevel surface 44 and aroundtip 46 (FIG. 12D) until the flat surface 41 on the end of the hookportion 22 engages the flat beveled surface 48 on the outside of the legmember 14 closing the clip (FIG. 12E). The channels 110' accommodate thebody of the clip within the jaws during the closing process. As bestseen in FIG. 12D, both leg members deflect under the forces exerted onthe clip during closure to accommodate movement of the hook portion ofleg member 12 around the tip of leg member 14.

The overall mechanics of clip closure were discussed in connection withFIGS. 12A through 12E. Referring now to FIGS. 13A through 13E, thefunctioning of the sharp penetrating members 43, 77 and 79, the groove61 and the sharp distal tip 31 will be described. The connective tissue302 is shown in each of the FIGS. 13A through 13E in between the distalend of leg member 14 and the hook portion 22 as the clip is closed. InFIG. 13A, before any contact is made between the leg members, the sharppoints 81 and 83 of the spaced apart penetrating members 77 and 79 ofthe second leg start to indent and penetrate the tissue 302 and pulltissue down, while in between the members 77 and 79, the sharp point 53of penetrating member 43 begins to penetrate the tissue and force thetissue up.

In FIG. 13B, the tip 53 enters the groove 61 on the second leg memberand puncturing of the tissue begins. In FIG. 13C, the penetrating member43 is moving through groove 61 and as penetrating members 77 and 79 moveclosely alongside the sides of the hook portion of the leg 12, shearforces contribute to puncturing of the tissue by the tips 81 and 83.After puncture, the knife-like edges of the penetrating member 77 and 79help to tear the tissue 302 as the leg 14 moves down. There is stilllittle or no contact between the penetrating member 43 and the groove61. The tissue caught between the distal end of the second leg and hookportion 22 begins to stretch. Tissue is jammed between three sharp edgeswhich move in opposite directions.

In FIG. 13D, if the tissue is not yet cut between the distal portion ofthe second leg member and the hook portion it will be stretched andbecome thinner and more easily punctured by the sharp point 31 of thedistal portion of the hook portion 22 as it passes through the groove 61and flat beveled surface 48. This point is quite sharp (less than 0.002inches) and cuts to remaining stretched tissue. The tissue which is veryelastomeric is made more penetrable by stretching. In FIG. 13E the finalstage of cutting and stretching is shown. If all the tissue is not cut,what remains will be quite thin, allowing the clip to latch.

FIG. 7 shows the clip closed about a vessel 300 which has been separatedfrom connective tissue 302 at least in the area of the clip. In thepreferred embodiment the radius of curvature of the inner convex surfaceof second leg member 14 is substantially the same as the radius ofcurvature of the inner concave surface of first leg member 12. Thiscauses a relatively even distribution across the width of the clampedvessel of the compressive forces being exerted by the clip leg members12 and 14. The vessel 300, particularly if large or upon swelling, willexert a counter force against the legs of the clip after applicationtending to open up the clip. The outer concave surface reduces thethickness of the second leg member such that it will deflect andlengthen in response to forces by the clamped vessel tending to open theclip. Lengthening of the second leg member moves the distal end of thesecond leg member farther into the hook portion. At the same time, theforces by the clamped vessel exerted on the first leg member will tendto shorten the first leg member moving the hook portion closer to thehinge and the distal end of the second leg member. This configurationprovides for a more secure latching. Also, because the thickness of thesecond leg member is smaller than it would have been without the concaveouter surface, and is substantially the same as the first leg memberbetween its inner and opposite outer surface, the total deflectionnecessary to accommodate closing and clamping of the vessel isdistributed between the two legs with a substantial amount of deflectionbeing taken up by second leg member helping to enhance the security ofthe latching effect and avoid premature failure of either leg. Thethickness of the second leg member in the center region is slightlylarger than the thickness of the first leg member or correspondingcenter region in order that the second leg member will bend slightlyless than the first leg member to avoid passing the flattening positionfrom which unlatching is facilitated. Both leg members can be made withequal thickness, however.

The inner surfaces of the side bosses 72 and 74 which extend beyond thetip 46 of the leg member 74 prevent the hook member 22 and leg member 14from moving laterally relative to one another, once the clip is closed.

By providing a continuous relatively large radii of curvature to boththe inner and outer surfaces of the hinge portion and the hook portion,sharp interior corners which create unwanted stress concentration, whichcan lead to clip failure, are eliminated.

Referring once again to FIG. 1 and 2, the clip 10 of FIG. 1 furtherincludes a plurality of protrusions 1302 on the inner surface 20 of theleg member 12, while leg member 14 includes a plurality of protrusions1304 on its inner surface 24. The protrusions are wedge shaped with thewedge opening up towards the hinge portion. The protrusions engage thetissue of the vessel being clamped and assist in preventing the vesselsliding laterally or longitudinally during or following clip closure. Itis preferable that the clip clamp the vessel substantially across thevessel at 90° to the axis of the vessel. The vessel being dynamic maymove or pulse and such movement may cause the clip to become misaligneddegrading its performance or function. The protrusions help inpreventing this.

FIG. 14 shows a side elevations view of the clip of FIG. 1 without thesharp penetrating member 43. Like parts are numbered the same in FIG. 14as in FIG. 2. While the sharp penetrating member adds to the penetrationof the connective tissue, particularly in stretching the tissue whichmakes it more susceptible to cutting by the sharp distal tip 31, it isbelieved that the member 43 is not absolutely necessary and that theclip will act satisfactorily without the member 43. One advantage to theembodiment of FIG. 14 is that there are NO protruding sharp memberspresent beyond the profile of the closed clip after the clip has beclamped about a vessel. This avoids possible damage to surroundingtissue by the protruding member 43.

The clip of FIGS. 1-14 is preferably a single integral piece of moldedplastic. The plastic material chosen is preferably one of the manyrelatively strong engineering plastics available today which arecommonly used in surgical implant operations and are biocompatible. Twoexamples of suitable plastics are polyethylene terephthalate (PET) andpolyoxymethylene. These are both thermoplastic materials that can beinjection molded, extruded or otherwise thermally processed into shapedarticles and filaments. An alternate, molding grade polyester,polybutylene terephthalate (PBT) can also be used.

As mentioned earlier it is preferable that any plastic surgical clip,such as a hemostatic clip, be as small as its metal equivalent. Thepreferred embodiment clip can be made as small as seven millimeters inoverall length in the closed position as measured from the back of thehinge to the outside of the hook portion. This is to be compared with amedium size metal hemostatic clip which is approximately six millimetersin length when closed. Each leg of the polymeric clip of the presentinvention has a maximum thickness in the order of 1.0 millimeters orless with a weight of about 0.015 grams, a volume of 0.01 cubiccentimeters and an opening of 4 millimeters or more.

In the preferred embodiment, the radius of curvature of the innersurface of the leg 12 starts out as 0.166 inches near the peninsularportion 56, changes to 0.222 inches at the center region up to the hookportion 22 where it changes to 0.052 inches and then to 0.007 inches.The outer surface of the hook portion starting at its end 32 is 0.045inches then 0.036 inches. As the hook portion ends and the outer surface30 of leg member 12 continues towards the hinge the radius of curvaturechanges from 0.108 inches, to 0.246 inches, to 0.171 inches near thehinge 16. The hinge's outer surface 52 has a radius of 0.042 inchesuntil the outer concave surface 38 of the leg member 14 begins at theradius of 0.161 inches and then 0.231 inches near the tip 46 (radius of0.003 inches). The radius of the curved beveled surface 44 is 0.044inches up until the start of the convex inner surface 24 of leg member14 which is 0.222 inches and then 0.166 inches. The radii are providedto give an example of the degree of curvature of the clip and to showthat the curved surfaces are generally continuous. The centers of theradii, even for the concave and convex surfaces, such as, the inner andouter surfaces of the leg members, are not generally the same. Whilethese radii reflect the radii for the preferred embodiment clip, itshould be understood that variations or changes from these radii areencompassed by the present invention curved clip.

While the embodiments of the surgical clip described herein above areparticularly adapted for hemostatic application, they may also haveother applications, e.g. as oviduct or vas deferens clips.

What is claimed is:
 1. A ligating clip applying instrument for applyingtwo legged ligating clips having engagement means on the lateral sidesof said legs comprising: a pair of handles pivoted about a hinge pointand extending beyond the hinge point to form a pair of clip closing jawshaving opposing inner faces, each of said jaws having a recessed clipreceiving channel in the inner face thereof extending from the tip ofsaid jaw rearward toward said hinge point, said channel having a lengthat least equal to the length of the clip to be applied by theinstrument; and each of said jaws comprising means for engaging saidclip engagement means, said means for engagement comprising each wall oneither said of said channel in each jaw comprising a concave cut outnear the end of said jaw and an arcuate wall portion adjacent to an onthe outside of said cut out.
 2. The instrument of claim 1 wherein theback wall of each concave cut out protrudes away from the channel in thedirection of said opposing jaw.
 3. The instrument of claim 2 wherein theheight of said adjoining arcuate wall portion is substantially equal tothe height of said protruding back wall.
 4. The instrument of claim 2wherein the bottom of the channel in each of said jaws forms aprotrusion directed toward said opposed jaw between the portions of saidcut outs which protrude toward said opposite jaw.
 5. A ligating clipapplying instrument for applying two legged ligating clips havingengagement means on the lateral sides of said legs comprising: a pair ofhandles pivoted about a hinge point and extending beyond the hinge pointto form a pair of clip closing jaws having opposing inner faces, each ofsaid jaws having a predetermined width and a clip receiving space in itsinner face extending from the tip of said jaw rearward toward said hingepoint, and each of said jaws provided with clip engagement means on itsinner face, said clip engagement means comprising a pair of spacedwalls, each wall having a concave cut out facing the opposing wall.
 6. Aligating clip applying instrument comprising: a pair of handles pivotedabout a hinge pivot and extending beyond the hinge point to form a pairof clip closing jaws having opposing inner faces, each of said jawshaving a pair of spaced walls adjacent the distal end thereof, each ofsaid walls being inwardly directed toward the opposite jaw and having arecess for receiving an engagement means affixed to the lateral side ofa ligating clip.
 7. A clip applying instrument according to claim 6wherein said instrument is adapted for use with a clip having aprojection adjacent and on each lateral side of the end of each clip legand wherein said recesses of said walls are adapted to receive saidprojections.